Background Art As well known to those skilled in the art, a plurality of fluid pipes are arrayed within an automobile to allow fluid to flow between a plurality of parts of the automobile. Such fluid pipes may be unexpectedly loosened, deformed or disassembled due to operational vibrations of the chassis, pressure and thermal stress caused by the fluid, such as gas or oil, flowing in the pipes. In the prior art, it is typical to connect the fluid pipes to the flanges of the parts of an automobile through a welding process in an effort to almost completely prevent a leakage of fluid from the pipes. However, such a welded structure of the pipes is not flexible, but is too stiff, thus easily failing to effectively absorb operational vibrations of the chassis. Therefore, the pipes, having such welded junctions, may be easily damaged, disassembled or broken at the welded junctions. The pipes, having such welded junctions, may be also easily deformed and damaged at the welded junctions due to repeated expansion and shrinkage caused by pressure and heat of fluid flowing in the pipes. This may finally allow a leakage of fluid from the deformed junctions of the pipes. It is thus necessary for the pipes of automobiles to have a desired rigid structure capable of appropriately absorbing

such a vibration impact and appropriately expanding and shrinking in response to thermal and pressure stress caused by the fluid flowing in the pipes.

Fig. 5 shows a conventional pipe coupling for fluid pipes in automobiles designed to endure such a vibration impact applied from the chassis, pressure and thermal stress of fluid flowing in the pipes.

As shown in the drawing, a rubber connection hose 200 is connected to opposing ends of two pipes 100, with opposite ends of the rubber connection hose 200 being fitted over the opposing ends of the two pipes 100. In such a case, the other ends of the two pipes 100 are welded to flanges of parts of an automobile.

A metal cap 300 is fitted over each of the opposite ends of the rubber connection hose 200 and is compressed to form a externally waved shape, thus accomplishing a firm and sealed coupling of the two pipes 100. In the above pipe coupling, the opposite ends of the rubber connection hose 200 are closely interposed between the metal caps 300 and the ends of the two pipes 100, and so the firm and sealed junctions between the rubber connection hose 200 and the two pipes 100 are accomplished.

In such a pipe coupling, vibration impact is directly applied from the chassis of an automobile to the pipes 100 and is, thereafter, directly transmitted to the rubber connection hose 200 from the pipes 100 during an operation of the engine. However, the flexible rubber connection hose 200 somewhat effectively absorbs such vibration impact. In addition, the rubber connection hose 200 also appropriately expands and shrinks in response to an expansion and shrinkage of the two pipes 100 due to pressure and thermal stress caused by fluid flowing in the pipes 100. Therefore, the above pipe coupling somewhat effectively prevents the welded junction between the pipes 100 and the flanges from being damaged by such vibration impact, pressure stress and thermal stress. That is, the conventional pipe coupling, composed of such a rubber connection hose 200, somewhat effectively accomplishes a desired pipe coupling structure, and somewhat appropriately endures vibration impact applied from the chassis,

pressure and thermal stress caused by fluid flowing in the pipes 100. However. the above pipe coupling is problematic in that it easily allows a leakage of fluid from the junctions between the pipe coupling and the pipes 100.

That is, the rubber connection hose 200 is made of a soft and flexible rubber material. However, it is very difficult to produce a desired rubber material by mixing components. Such rubber connection hoses 200 are very limited in their use, and so there is a remarkable difference in quality between the connection hoses 200 and typically used rubber packing rings. It is thus very difficult to form a desired connection hose having a circular cross-section using a conventional rubber. Therefore, it is necessary to mix an additive, such as styrene butadiene rubber or chloroprene rubber, into the material of the connection hoses 200 during a process of forming the connection hoses 200 in an effort to improve the quality of final products. However, such a mixing of the additive with the material of the connection hoses 200 is very difficult, and so it is almost impossible to accomplis a desired thermal resistance and a desired durability of final products. Therefore, the conventional rubber connection hoses 200 may be easily damaged and deformed due to both the chemical toxicity of fluid flowing in the pipes and thermal stress caused by said fluid, thus easily allowing a leakage of fluid from the pipes. Particularly, such a rubber connection hose 200 is more easily deformed at its ends, at which the connection hose 200 is brought into contact with the pipes 100. Therefore, the fluid easily undesirably leaks from the pipes 100 into the atmosphere through the junctions between the pipes 100 and the rubber connection hose 200 as shown by the arrow of Fig. 5. In a brief description, the conventional pipe coupling, having such a rubber connection hose 200, somewhat effectively retains a desired structural stability when it is newly installed within an automobile, but undesirably allows a fluid leakage from the pipes 100 after being used for a period of time. This forces a user to frequently repair or change the pipe coupling while paying excessive money. In addition. the metal caps 300, fitted over the opposite ends of the rubber connection hose

200, are tightly compressed to form waved junctions, and so it is very difficult for the user to disassemble the rubber connection hose 200 from the pipes 100 when repairing or changing the connection hoses 200.

Disclosure of the Invention Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a universal pipe coupling for fluid pipes in automobiles, which uses a metal connection hose in place of the conventional rubber connection hose, and movably and rotatably connects two fluid pipes to opposite ends of the metal connection hose, thus allowing the fluid pipes to be smoothly rotatable around the connection hose in response to vibration impact applied from the chassis of an automobile to the pipes and allowing both the pipes and the connection hose to effectively expand or shrink in an axial direction and/or a radial direction in response to pressure and/or thermal stress caused by fluid flowing in the pipes and thereby allowing the pipes to maintain their desired operational function regardless of such vibration impact, pressure and/or thermal stress.

In an embodiment of the present invention, the universal pipe coupling for fluid pipes in automobiles is composed of an enlarged-diameter end portion formed at each of the opposing ends of two pipes by enlarging the opposing ends of the two pipes in diameter, with a stop washer being set in each of the enlarged- diameter end portions. This pipe coupling also has a metal connection hose. which is fitted into the enlarged-diameter end portions of the two pipes at its opposite ends, with a packing ring being fitted over each end of the metal connection hose and being brought into close contact with the internal surface of the enlarged-diameter end portion of an associated pipe.

In another embodiment, the enlarged-diameter end portions are formed at the opposite ends of the metal connection hose, and the opposing ends of the two

pipes are fitted into the enlarged-diameter end portions of the metal connection hose, with the packing rings being fitted over the opposing ends of the pipes and being brought into close contact with the internal surfaces of the enlarged-diameter end portions of the metal connection hose.

Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a sectional view, showing the construction of a universal pipe coupling in accordance with the primary embodiment of the present invention; Figs. 2a to 2c are sectional views, showing an operation of the pipe coupling of Fig. 1; Fig. 3 is a sectional view, showing the construction of a universal pipe coupling in accordance with the second embodiment of the present invention; Figs. 4a and 4b are sectional views, showing an operation of the pipe coupling of Fig. 3; and Fig. 5 is a sectional view, showing the construction of a conventional pipe coupling for fluid pipes in automobiles.

Best Mode for Carrving Out the Invention Fig. 1 is a sectional view, showing the construction of a universal pipe coupling for fluid pipes in automobiles in accordance with the primary embodiment of the present invention. This pipe coupling is constructed as follows. As shown in the drawing, the end of each pipe 10 is enlarged in diameter, thus forming an enlarged-diameter end portion 11, while a metal connection hose 20 is fitted into the enlarged-diameter end portions 11 of two

pipes 10 at opposite ends thereof, with a packing ring 30 being tightly fitted over each end of the metal connection hose 20 and being brought into close contact with the internal surface of the enlarged-diameter end portion 11 of an associated pipe 10, thus accomplishing a desired sealing effect at the junctions between the pipes 10 and the rnetal connection hose 20.

Fig. 3 is a sectional view, showing the construction of a universal pipe coupling for fluid pipes in automobiles in accordance with the second embodiment of the present invention. The pipe coupling according to the second embodiment is constructed as follows. As shown in the drawing, a packing ring 30 is tightly fitted over the end of each pipe 10, while the opposite ends of a metal connection hose 20 are enlarged in diameter, thus forming enlarged-diameter end portions 21.

The ends of two pipes 10 are fitted into the enlarged-diameter end portions 21 of the metal connection hose 20 in a way such that the packing rings 30 of the two pipes 10 are brought into close contact with the internal surfaces of the enlarged- diameter end portions 21 of the metal connection hose 20. Therefore, a desired sealing effect at the junctions between the pipes 10 and the metal connection hose 20 is accomplished. In the two embodiments of this invention, a stop washer 40 is set in each of the enlarged-diameter end portions 11 and 21, thus preventing the metal connection hose 20 from being undesirably removed from the pipes 10. In the primary embodiment, two parallel annular rings"a"are externally formed on the external surface of each end portion of the metal connection hose 20, thus defining a ring seat between them and stably seating a packing ring 30 on the ring seat. In the same manner, two parallel annular rings"a"are externally formed on the external surface of the end portion of each pipe 10 in the second embodiment, thus defining a ring seat between them and stably seating a packing ring 30 on the ring seat.

In the drawings, the reference numeral 50 denotes a mount bracket used for mounting the metal connection hose 20 to the chassis of an automobile.

In the present invention, the packing rings 30 are made of natural rubber,

which has been typically and generally used in a variety of industrial fields. Such natural rubber is easily formed as desired products using a simple molding machine, and so it is easy to mix desired additives, such as styrene butadiene rubber, with the natural rubber. Therefore, the packing rings 30 of this invention have a desired thermal resistance, a desired durability and a desired flexibility.

Such packing rings 30 are thus almost free from being thermally and plastically deformed due to the high degree of thermal resistance and the high degree of durability. On the other hand, the high degree of flexibility of the packing rings 30 allows the rings 30 to maintain a desired elasticity for a lengthy period of time, and so the packing rings 30 retain a desired sealing effect at the junctions between the rings 30 and the internal surfaces of the enlarged-diameter end portions 11,21 for a lengthy period of time.

Figs. 2a to 2c are sectional views, showing an operation of the pipe coupling of Fig. 1. Figs. 4a and 4b are sectional views, showing an operation of the pipe coupling of Fig. 3.

In the case of the pipe coupling according to the primary embodiment, at least one of the two pipes 10, connected to the opposite ends of the metal connection hose 20, is smoothly rotatable around the connection hose 20 in an impacted direction as shown in Figs. 2a and 2b when vibration impact is applied from the chassis of an automobile to the pipes 10, thus effectively absorbing the vibration impact.

In the pipe coupling according to the primary embodiment, the opposite ends of the metal connection hose 20 are not directly connected to the enlarged- diameter end portions 11 of the two pipes 10, but are simply and movably fitted into the end portions 11 of the pipes 10, with the packing rings 30 of the connection hose 20 coming into close contact with the internal surfaces of the end portions 11. Therefore, the two pipes 10 may be movable and rotatable in any direction at their enlarged-diameter end portions 11 around the opposite ends of the metal connection hose 20 fixedly mounted to the chassis of an automobile

through the mount bracket 50. Even when the packing rings 30 of the connection hose 20 are fitted into the enlarged-diameter end portions 11 of the two pipes 10 in the primary embodiment of this invention, the desired sealing effect at the junctions between the packing rings 30 and the internal surfaces of the enlarged- diameter end portions 11 of the two pipes 10 is effectively maintained for a desired lengthy period of time due to the high degree of elasticity of the packing rings 30.

In addition, the internal surfaces of the enlarged-diameter end portions 11 of the two pipes 10 are easily and smoothly movable on the circumferential surfaces of the packing rings 30, and so the two pipes 10, connected to the opposite ends of the metal connection hose 20, are smoothly rotatable around the connection hose 20 in an impacted direction when vibration impact is applied from the chassis of the automobile to the pipes 10. In other words, when vibration impact is applied from the chassis to the pipes 10 during a running operation of the automobile, the two pipes 10 are smoothly rotatable around the connection hose 20 in an impacted direction while effectively absorbing the vibration impact. Such an operational effect of the pipe coupling of this invention is the same as that expected from conventional universal joints. Automobiles are repeatedly vibrated in every direction with a variety of intensities of vibration impact while running on streets.

The pipe coupling of this invention is designed to allow the pipes 10 to be repeatedly and continuously movable and rotatable around the opposite ends of the fixed connection hose 20 in an impacted direction in response to vibration impact applied from the chassis to the pipes 10. The pipe coupling thus effectively absorbs such vibration impact without allowing the impact to ill-affect the pipes 10. Such an effective absorption of vibration impact expected by the pipe coupling of this invention maintains a desired structure of the welded junctions between the pipes 10 and the parts of the automobile for a desired lengthy period of time. This finally increases the expected life span of the welded junctions of the pipes 10.

The rotating angles of the pipes 10 around the fixed connection hoses 20

are changed in response to the intensity of vibration impact applied to the pipes 10.

Therefore, one of the two pipes 10 may be smoothly rotatable around the fixed connection hose 20 in an impacted direction as shown in Fig. 2a in accordance with the intensity and acting direction of vibration impact applied to the two pipes 10. On the other hand, the two pipes 10 may be commonly rotatable around the fixed connection hose 20 in an impacted direction as shown in Fig. 2b. Such a smooth rotating action of the pipes 10 around the fixed connection hose 20 is continued during an application of the vibration impact from the chassis to the pipes 10.

On the other hand, Fig. 2c shows an operation of the pipe coupling according to the primary embodiment of this invention when the pipes 10 expand or shrink in response to pressure and/or thermal stress caused by fluid flowing in the pipes 10. When it is desired for the pipes 10 to expand or shrink in response to the pressure and/or thermal stress caused by the fluid flowing in the pipes 10. the two pipes 10 easily, smoothly and effectively expand or shrink in a desired direction, or an axial direction and/or a radial direction, since the enlarge-diameter end portions 11 of the two pipes 10 are not fixed to the connection hose 20, but are simply fitted over the opposite ends of the connection hose 20 with the elastic packing rings 30 being closely interposed between them. In such a case, the pressure and/or thermal stress caused by the fluid acts on the entire surface of the two pipes 10, but is concentrated to physically weak portions of the pipes 10.

Therefore, the pipes 10 practically and mainly expand or shrink at the enlarged- diameter end portions 11 in response to the pressure and/or thermal stress of the fluid since the end portions 11 are movably held on the fixed connection hose 20 and are larger in diameter than the other portions of the pipes 10. Therefore, the two pipes 10 easily, smoothly and effectively expand or shrink in a desired direction, or an axial direction and/or a radial direction, without failure as shown by the arrow of Fig. 2c in response to the pressure and/or thermal stress caused by the fluid flowing in the pipes 10. When the enlarged-diameter end portions 11 of

the pipes 10 expand in a radial direction as described above, the connection hose 20 expands in the same direction. Therefore, the packing rings 30 are not separated from the intemal surfaces of the end portions 11 of the pipes 10. On the other hand, the radial expansion of the connection hose 20 may be less than that of the end portions 11 of the pipes 10. In such a case, the packing rings 30 continuously come into close contact with the internal surfaces of the end portions 11 since the rings 30 are elastically restored to their original volumes. The sealing effect at the junctions between the packing rings 30 and the internals surfaces of the end portions 11 is thus always accomplished regardless of such radial expansion of the end portions 11 of the pipes 10. On the other hand, when the enlarged-diameter end portions 11 of the pipes 10 shrink in a radial direction due to pressure and/or thermal stress, the connection hose 20 shrinks in the same direction. Therefore, the packing rings 30 are not separated from the internal surfaces of the end portions 11 of the pipes 10. When the radial shrinkage of the connection hose 20 is less than that of the end portions 11 of the pipes 10, the packing rings 30 are further compressed to the internal surfaces of the end portions 11, thus accomplishing a desired sealing effect at the junctions between the paclcing rings 30 and the internal surfaces of the end portions 11 without failure.

As described above, the pipe coupling according to the primary embodiment of this invention allows the pipes 10 to be easily, smoothly and effectively expandable or shrinkable at their enlarged-diameter end portions 11 in response to pressure and/or thermal stress caused by fluid flowing in the pipes 10. The pipes 10 are thus almost completely free from being deformed or damaged regardless of pressure and/or thermal stress caused by the fluid flowing in the pipes 10. The pipe coupling also allows the packing rings 30 to always and continuously come into close contact with the internal surfaces of the enlarged-diameter end portions even in the case of radial expansion or shrinkage of both the pipes 10 and the connection hose 20.

Fig. 3 shows the construction of the pipe coupling according to the second

embodiment of this invention. Figs. 4a and 4b show an operation of the pipe coupling of Fig. 3.

In the pipe coupling according to the second embodiment, the opposite ends of the metal connection hose 20 are enlarged in diameter, thus forming the enlarged-diameter end portions 21 as shown in Fig. 3. A packing ring 30 is tightly fitted over the end of each pipe 10. The opposing ends of the two pipes 10 are fitted into the enlarged-diameter end portions 21 of the metal connection hose 20, with the packing rings 30 of the two pipes 10 being brought into close contact with the internal surfaces of the enlarged-diameter end portions 21 of the metal connection hose 20 and accomplishing a desired sealing effect at the junctions between the pipes 10 and the metal connection hose 20. In the pipe coupling according to the second embodiment, the structure of the coupling is altered to be opposed to that of the primary embodiment, but the operational function of the second embodiment remains the same as that described for the primary embodiment as will be described later herein. It is thus possible for a user to freely select and use a desired one of the two types of pipe couplings in accordance with types of automobiles and his personal requirements. When vibration impact is applied from the chassis of an automobile to the pipes 10 connected together using the pipe coupling of Fig. 3, at least one of the two pipes 10, connected to the opposite ends of the metal connection hose 20, is smoothly rotatable around the connection hose 20 in an impacted direction as shown in Figs. 4a and 4b, thus effectively absorbing the vibration impact. That is, the operational function of the pipe coupling according to the second embodiment remains the same as that described for the primary embodiment, but the rotating action of the two pipes 10 in the second embodiment is performed within the opposite ends of the connection hose 20 different from the primary embodiment, in which the rotating action of the two pipes 10 are performed outside the opposite ends of the connection hose 20.

In addition to the rotating action caused by the vibration impact applied from the chassis to the pipes 10, the pipe coupling of this second embodiment allows the

two pipes 10 to effectively expand or shrink in an axial direction and/or a radial direction while retaining a desired sealing effect in response to the pressure and/or thermal stress caused by fluid flowing in the pipes 10 in the same manner as that described for the primary embodiment. Further explanation is thus not deemed necessary.

In a pipe coupling according to the present invention, the packing rings 30 are made of natural rubber different from a conventional rubber connection hose 200 of Fig. 5. The packing rings 30 of this invention are thus easily formed through a molding process using the natural rubber easily mixed with 20 wt% of additives different from the material of the conventional rubber connection hoses 200. Therefore, the packing rings 30 have a desired thermal resistance and a desired durability. When two pipes 10 are connected together by a metal connection hose 20 with such packing rings 30 being closely interposed between the pipes 10 and the connection hose 20, the packing rings 30 are not undesirably deformed by fluid flowing in the pipes 10, but maintain a desired sealing effect between the pipes 10 and the connection hose 20 for a desired lengthy period of time. This finally increases the expected life span of the pipes 10.

In a pipe coupling according to this invention, a stop washer 40 is set in each of the enlarged-diameter end portions 11 and 21, thus preventing the metal connection hose 20 from being undesirably removed from the pipes 10. That is. when excessive vibration impact is applied from the chassis of an automobile tc the pipes 10 in the case of, for example, safety hazards of the automobile, the connection hose 20 may be undesirably removed from the pipes 10. However, the pipe coupling of this invention effectively prevents such an undesirable removal of the connection hose 20 from the pipes 10 by the stop washers 40, which come into contact with and stop the parallel annular rings"a"of the ring seats for the packing rings 30 in such an accidental case. Due to the stop washers 40, it is possible to almost completely prevent the connection hose 20 from being undesirably removed from the pipes 10, and so the pipe coupling of this invention

prevents fire caused by fluid undesirably leaking from the pipes 10 causing safety hazards of automobiles.

Industrial Applicability As apparent from the above description, the present invention provides a universal pipe coupling for fluid pipes in automobiles. The pipe coupling of this invention uses a metal connection hose in place of the conventional rubber connection hose. In the pipe coupling of this invention, two fluid pipes are movably and rotatably connected to opposite ends of the metal connection hose, with packing rings closely interposed at the junctions between the pipes and the connection hose. The pipe coupling thus accomplishes a desired sealing effect at the junctions while effectively absorbing vibration impact applied from the chassis of an automobile to the pipes and almost completely preventing damage of the fluid pipes regardless of such vibration impact. In the pipe coupling, both the pipes and the connection hose are allowed to effectively expand or shrink in an axial direction and/or a radial direction in response to pressure and/or thermal stress caused by fluid flowing in the pipes, and so the pipes are almost completely free from fluid leakage, deformation or undesirable removal from the connection hose for a desired lengthy period of time. The fluid pipes, connected together using the pipe coupling of this invention, are thus usable without being changed with new pipes or being frequently repaired, and so the pipe coupling reduces the maintenance cost of such fluid pipes and allows users to have mental comfort while driving cars.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.